Grease or the like has been heretofore applied between the shaft and its bearing of a rotary electronic part such as a potentiometer to allow a torque to be delivered from the part, but the torque obtained is 200 g.multidot.cm at best. There is a demand for much greater torque in cases where the design of the electronic device requires a large knob to be mounted or where the torque must be matched to the larger torque of its neighboring electronic part.